Article 430 Motors, Motor Circuits, and Controllers
Informational Note No. 2: Figure 430.1 is for information only.
|General, 430.1 through 430.18||Part I|
|Motor Circuit Conductors, 430.21 through 430.29||Part II|
|Motor and Branch-Circuit Overload Protection, 430.31 through 430.44||Part III|
|Motor Branch-Circuit Short-Circuit and Ground-Fauit Protection, 430.51 through 430.58||Part IV|
|Motor Feeder Short-Circuit and Ground-Fault Protection, 430.61 through 430.63||Part V|
|Motor Control Circuits, 430.71 through 430.75||Part VI|
|Motor Controllers, 430.81 through 430.90||Part VII|
|Motor Control Centers, 430.92 through 430.99||Part VIII|
|Disconnecting Means, 430.101 through 430.113||Part IX|
|Adjustable-Speed Drive Systems, 430.120 through 430.131||Part X|
|Over 1000 Volts, Nominal, 430.221 through 430.227||Part XI|
|Protection of Live Parts—All Voltages, 430.231 through 430.233||Part XII|
|Grounding—All Voltages, 430.241 through 430.246||Part XIII|
|Tables, Tables 430.247 through 430.252||Part XIV|
FIGURE 430.1 Article 430 Contents.
Electronically Protected (as applied to motors). A motor that is provided with electronic control that is an integral part of the motor and protects the motor against dangerous overheating due to failure of the electronic control, overload and failure to start.
Part-Winding Motors. A part-winding start induction or synchronous motor is one that is arranged for starting by first energizing part of its primary (armature) winding and, subsequently, energizing the remainder of this winding in one or more steps. A standard part-winding start induction motor is arranged so that one-half of its primary winding can be energized initially, and, subsequently, the remaining half can be energized, both halves then carrying equal current.
Informational Note: A hermetic refrigerant motor-compressor is not considered a standard part-winding start induction motor.
System Isolation Equipment. A redundantly monitored, remotely operated contactor-isolating system, packaged to provide the disconnection/isolation function, capable of verifiable operation from multiple remote locations by means of lockout switches, each having the capability of being padlocked in the "off' (open) position.
Valve Actuator Motor (VAM) Assemblies. A manufactured assembly, used to operate a valve, consisting of an actuator motor and other components such as controllers, torque switches, limit switches, and overload protection.
Informational Note: VAMs typically have short-time duty and high-torque characteristics.
Exception: A short-circuit and ground-fault protective device shall be permitted for both windings if the device will allow the motor to start. Where time-delay (dual-element) fuses are used, they shall be permitted to have a rating not exceeding 150 percent of the motor full-load current.
Table 430.5 Other Articles
|Air-conditioning and refrigerating equipment||440|
|Commercial garages; aircraft hangars; motor fuel dispensing facilities; bulk storage plants; spray application, dipping, and coating processes; and inhalation anesthetizing locations||511, 513, 514, 515, 516, and 517 Part IV|
|Cranes and hoists||610|
|Electrically driven or controlled irrigation machines||675|
|Elevators, dumbwaiters, escalators, moving walks, wheelchair lifts, and stairway chair lifts||620|
|Hazardous (classified) locations||500—503, 505, and 506|
|Motion picture projectors||540.11 and 540.20|
|Motion picture and television studios and similar locations||530|
|Resistors and reactors||470|
|Theaters, audience areas of motion picture and television studios, and similar locations||520.48|
|Transformers and transformer vaults||450|
Exception No. 2: For equipment that employs a shaded-pole or permanent-split capacitor-type fan or blower motor that is marked with the motor type, the full load current for such motor marked on the nameplate of the equipment in which the fan or blower motor is employed shall be used instead of the horsepower rating to determine the ampacity or rating of the disconnecting means, the branch-circuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and the separate overload protection. This marking on the equipment nameplate shall not be less than the current marked on the fan or blower motor nameplate.
Exception No. 3: For a listed motor-operated appliance that is marked with both motor horsepower and full-load current, the motor full-load current marked on the nameplate of the appliance shall be used instead of the horsepower rating on the appliance nameplate to determine the ampacity or rating of the disconnecting means, the branch-circuit conductors, the controller, the branch-circuit short-circuit and ground-fault protection, and any separate overload protection.
- Manufacturer's name.
- Rated volts and full-load current. For a multispeed motor, full-load current for each speed, except shaded-pole and permanent-split capacitor motors where amperes are required only for maximum speed.
- Rated frequency and number of phases if an ac motor.
- Rated full-load speed.
- Rated temperature rise or the insulation system class and rated ambient temperature.
- Time rating. The time rating shall be 5, 15, 30, or 60 minutes, or continuous.
- Rated horsepower if 1/8 hp or more. For a multispeed motor 1/8 hp or more, rated horsepower for each speed, except shaded-pole and permanent-split capacitor motors 1/8 hp or more where rated horsepower is required only for maximum speed. Motors of arc welders are not required to be marked with the horsepower rating.
- Code letter or locked-rotor amperes if an alternating-current motor rated 1/2 hp or more. On polyphase wound-rotor motors, the code letter shall be omitted.
Informational Note: See 430.7(B).
- Design letter for design B, C, or D motors.
Informational Note: Motor design letter definitions are found in ANSI/NEMA MG 1—1993, Motors and Generators, Part 1, Definitions, and in IEEE 100—1996, Standard Dictionary of Electrical and Electronic Terms.
- Secondary volts and full-load current if a wound-rotor induction motor.
- Field current and voltage for dc excited synchronous motors.
- Winding — straight shunt, stabilized shunt, compound, or series, if a dc motor. Fractional horsepower dc motors 175 mm (7 in.) or less in diameter shall not be required to be marked.
- A motor provided with a thermal protector complying with 430.32(A)(2) or (B)(2) shall be marked "thermally protected." Thermally protected motors rated 100 watts or less and complying with 430.32(B)(2) shall be permitted to use the abbreviated marking "T.P."
- A motor complying with 430.32(B)(4) shall be marked "impedance protected." Impedance-protected motors rated 100 watts or less and complying with 430.32(B)(4) shall be permitted to use the abbreviated marking "Z.P."
- Motors equipped with electrically powered condensation prevention heaters shall be marked with the rated heater voltage, number of phases, and the rated power in watts.
- Motors that are electronically protected from overloads in accordance with 430.32(A)(2) and (B)(2) shall be marked "electronically protected" or "E.P."
The code letter indicating motor input with locked rotor shall be in an individual block on the nameplate, properly designated.
Table 430.7(B) Locked-Rotor Indicating Code Letters
|Code Letter||Kilovolt-Amperes per Horsepower with Locked Rotor|
|V||22.4 and up|
Exception: Constant horsepower multispeed motors shall be marked with the code letter giving the highest locked-rotor kilovolt-ampere (KVA) per horsepower (hp).